Existing home sales fell in May as the housing market may be on the brink of taking another dive. Last month’s sales dropped 2.2 percent compared to the previous month to a seasonally adjusted annual rate of 5.66 million according to a National Association Realtors report released Tuesday.

Year-over-year sales were up 19.2 percent to an annual rate of 6.1 million units.

Existing home sales data is based on transaction closings, so figures still reflect strong interest for the $8,000 tax credit where homebuyers had to sign contracts by the end of April but have until the end of June to close deals.

So the tax credit, stabilizing home prices and low mortgage rates kept sales at elevated levels last month, said Lawrence Yun, NAR chief economist.

"We are witnessing the ongoing effects of the homebuyer tax credit, which we'll also see in June real estate closings," Yun said.

The Senate is in the process of passing an amendment to push back the closing deadline to September 30 as part of a controversial job and tax bill.

Also in the NAR report was the median price of homes sold in May were it was up 2.7 percent up from a year ago to $179,600.

Total housing inventory dropped 3.4 percent to 3.89 million existing homes for sale which represents an 8.3-month supply at the current sales pace, down from a 8.4-month supply in April.

Considered normal homes inventory is a six month of supply.

Sales of single-family homes dropped 1.6 percent in May compared to the prior month, while condominium and co-op sales fell nearly 7 percent.

Regionally, Northeast had the biggest drop as it registered an 18.3 percent drop to an annual level of 890,000 units in May. That's still 12.7% higher than a year earlier.

In the Midwest, sales were unchanged in May from the previous month at an annual pace of 1.33 million units.

Sales increased 0.5 percent in the South and 4.9 percent in the West.